The Louisiana Supreme Court will hear arguments on Monday in a death penalty appeal that targets a Confederate flag flying outside the courthouse in Caddo Parish.

Lawyers for Felton Dorsey, a black man convicted of killing a white firefighter, will argue that the flag intimidates African Americans from serving on juries, report the Associated Press and the Shreveport Times. Juror Carl Staples was struck as a potential juror in Dorsey’s 2009 trial after he objected to the flag.

The Confederate flag was raised at the courthouse in 1951 during a protest of the civil rights movement. It flies beside a 1903 monument honoring Caddo Parish as the last stand of Confederate Louisiana.

The ACLU cites research by a Florida State University professor who found that whites express more negative attitudes toward African-Americans after exposure to images of the Confederate flag.

“The Confederate flag flies outside the courthouse and is visible to all who walk through its doors,” the brief says. “Its presence creates an intolerable risk under the Eighth Amendment that criminal justice cannot be fairly administered within the courthouse walls, particularly in death penalty cases.”